Barnard 169 (with 170, 171, 173, 174, and 368) (Gary Imm)

Barnard 169 (with 170, 171, 173, 174, and 368)

This image captures a dark nebulae complex located in the constellation of Cepheus at a latitude of +59 degrees.

As shown on the annotated mouseover, the image includes Barnard dark nebulae 169 through 174 (except for 172), plus 368. Where is 172 you ask? Barnard 172 does not exist. I do not understand why is does not exist. DSO designations are full of intrigue and mystery.

Another mystery is the definition of Barnard 169. That has bothered me for a long time. Some people ponder on politics or religion - I lose sleep over DSO designations.

Sources, including the Barnard atlas, show Barnard 171 to be the large squarish dark patch just left of center, and Barnard 170 to be the irregular diagonal dark patch just to the right of B171. Puzzling is that these same sources show B169 to be the island of bright stars in the center of the image. That never made sense to me, since B169 is supposed to be a dark nebula, not bright stars!

The answer to this mystery comes in the text buried in Barnard's atlas, which reads for B169:
Elliptical black ring, diam 1°.
This encloses an 'island' of small stars.
The dark ring is broadest on its east side where its thickness is 22'.
The northern part is very black and straight.

So there you have it. B169 is not the "island" but the black ring around the island, which therefore also includes B170 and B171. Surprisingly, the Astrobin mouseover annotation gets it exactly right above.

I really don't like it when a catalogue object includes aspects of other objects - this happens occasionally in most catalogues, including Sh2 and Gum. I will have to get over that.

These objects are adjacent to the IC 1396 (Elephant Trunk) complex, which is just to the lower right off frame. Some faint HII nebulosity can be seen throughout of the image, including LBN 474 at lower left.

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Status	Advanced success
Started	...
Astrometry.net job	9158404
PixInsight job	FWOIM8Y3ZW37I0ISUYN2XJDXUNWXIXKF
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	21h59m16s.38
RA (top/left)	22h10m18s.18
RA (top/right)	21h48m39s.80
RA (bottom/right)	21h48m50s.32
RA (bottom/left)	22h09m16s.68

Dec (center)	+58°48′23″.8
Dec (top/left)	+59°44′22″.5
Dec (top/right)	+59°48′59″.9
Dec (bottom/right)	+57°49′05″.0
Dec (bottom/left)	+57°44′42″.8

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